Description, causes, prevention, treatment and medicines
A dry cough is a cough where no phlegm or mucus is produced (known as non-productive). A dry cough is irritating, usually with a tickly throat.
How long does a cough normally last?
Coughs associated with a cold or the flu tend to last a week or 2, most clearing up within about 3 weeks. A post-viral cough may persist for several (up to about 8) weeks after a viral illness, while some coughs persist for longer and are usually a sign of an underlying problem.
In adults and children, a cough is described as acute (short term) if you have been coughing for up to 2 weeks.
In adults, a cough that lasts for more than 8 weeks is described as a chronic (ongoing) persistent cough.
In children, a cough that lasts 2 to 4 weeks is called a prolonged acute cough. A cough that lasts more than 4 weeks is considered to be a chronic cough.
Causes of dry cough
A dry cough is often the result of:
- a viral illness, such as a cold or influenza (the flu); or
- a post-viral, or post-infective, cough (cough that persists for weeks after a viral illness).
However, a dry cough may be a result of other problems, such as:
- asthma;
- gastro-oesophageal reflux;
- smoking;
- allergic rhinitis (hay fever) due to inhaling substances you are allergic to, such as pollen, dust or pet dander;
- post-nasal drip (the drainage of mucus secretions from the nose or sinuses down the back of the throat);
- laryngitis (inflammation of the larynx, also known as the voice box);
- whooping cough;
- obstructive sleep apnoea and snoring;
- habit cough (a cough that is only present in the daytime and not caused by illness – it most often affects school-aged children);
- certain types of lung disease known as interstitial lung disease; or
- a side effect from a medicine (for example, cough is a possible side effect of most ACE inhibitors – often prescribed for high blood pressure).
Other, less common, causes of a dry cough include:
- heart failure;
- pulmonary embolism (a blood clot in the lungs); or
- lung cancer.
A dry cough can be aggravated by:
- breathing cold, dry air;
- air pollution;
- inhaled irritants such as dust or smoke;
- exposure to tobacco smoke;
- excessive use of your voice; or
- a change in temperature.
Complications
A persistent dry cough can cause problems, including the following complications.
- Repeated coughing can lead to urinary incontinence in women, especially older women, pregnant women and those who have been pregnant.
- Interrupted sleep resulting in tiredness is a common problem for people with a persistent cough.
- Severe or uncontrollable coughing fits can sometimes cause vomiting.
- Headaches may result from a persistent cough.
Can I hurt myself coughing?
When a cough is severe, pulled chest muscles and even fractured ribs are a possible complication.
Diagnosis and tests
Your doctor will ask about your cough and any other symptoms you may have, and perform a physical examination. Depending on your age, history and examination, your doctor may order tests such as:
- a chest X-ray;
- a throat swab (sample of secretions from the back of your throat which can be tested for infections);
- lung function tests; or
- allergy tests.
Dry coughs are often related to a viral illness and in most cases special tests are not needed.
When should you seek medical advice about a dry cough?
You should you seek medical advice if:
- you start to cough up blood or copious amounts of mucus (phlegm);
- you are short of breath or wheezy;
- the cough is mainly at night;
- you have associated chest pain;
- you have a fever;
- you are a cigarette smoker;
- you have a hoarse voice;
- the cough is associated with vomiting or a choking sensation;
- you have other symptoms such as an ongoing headache, sore ears or a rash;
- you have recently lost weight or have general muscle aches;
- the cough is in an infant aged 6 months or younger;
- the cough has lasted longer than 10 days, with little or no improvement; or
- you have high blood pressure, a heart complaint, respiratory illness (such as asthma), gastric problems or are taking other medicines.